jimmy, i believe you are right about the bushings. I must admit that at times, when starting the car, the blower motor does not blow and the remedy is to open/slam closed the glove box or slap the panel under the glove box.
This ALWAYS kick starts the blower into working!!
QUESTION: Would it be ok ...

I am the original owner of a 2004 2.5T XC90. Can you suggest a resolution to this?
When driving with the AC running, when I make turns or break for traffic, the fan blower
speed lowers and slightly raises repeatedly. After several seconds of this undulating, the
blower speed returns back up to the ...

Yes, this a bad CV axel. The inside "cage" of the axel has some play in it and causes this problem. There could also be end play in the axel, a small amount can cause problems with the balance of the spinning axel. Replace the suspect one. This fix my same problem.